An efficient microfluidic sorter: implementation of double meandering micro striplines for magnetic particles switching

Abstract

The ability to trap, manipulate, and separate magnetic beads has become one of the key requirements in realizing an integrated magnetic lab-on-chip biosensing system. In this article, we present the design and fabrication of an integrated magneto-fluidic device for sorting magnetic particles with a sorting efficiency of up to 95%. The actuation and manipulation of magnetic beads are realized using microfabricated square meandering currentcarrying micro striplines. The current is alternated between two neighboring micro striplines to switch the magnetic beads to either one of the two outlets. We performed a series of parametric study to investigate the effect of applied current, flow rate, and switching frequency on the sorting efficiency. Experimental results reveal that the sorting efficiency is proportional to the square of current applied to the stripline, and decreases with increasing buffer flow rate and switching frequency. Such phenomena agree well with our theoretical analysis and simulation result. The fastest switching rate, which is limited by the microchannel geometry and bead velocity, is 2 Hz.

Micro-magnetofluidics: interactions between magnetism and fluid flow on the microscale

“…Besides ferromagnetic structures, current conducting electro magnet in form of microcoils (Song et al 2009) or micro-stripes (Kong et al 2011;Derec et al 2010) (Fig. 8g) also have been used for magnetophoretic separation.…”

Microdevice for continuous flow magnetic separation for bioengineering applications

“…Active elements are primarily electromagnets that consume energy in addition to requiring complex microfabrication processes for their creation [13][14][15]. An advantage of electromagnets is that they can be switched on and off easily.…”

Electromagnetic–mechanical desalination: Mathematical modeling

“…Soft passive magnetic element can be integrated into a fluidic system via deposition on the separation cell, and an external bias field is used to magnetize the soft element [20][21][22][23][24][25][26]. An advantage to this method is ability to switch on/off the magnetic field by applying or removing the external bias field.…”

“…In addition, the magnetic force can also be applied via an active magnetic element in which voltage is driven in coils or conductors. The active magnetic element can be switched on and off as needed by supplying the voltage to the coils or conductors [20,22].…”

“…Several researchers have studied magnetic separation in micro fluid system [20][21][22][23][24][25][26][35][36]. Choi et al studied the capture of magnetic beads in micro fluid system via an active magnet for bioseparation applications [20,21].…”